/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements.  See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership.  The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License.  You may obtain a copy of the License at
*
*     http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

package org.apache.hadoop.hbase.zookeeper.client.common;

/**
 * Path related utilities
 */
public class PathUtils {

	/** validate the provided znode path string
	 * @param path znode path string
	 * @param isSequential if the path is being created
	 * with a sequential flag
	 * @throws IllegalArgumentException if the path is invalid
	 */
	public static void validatePath(String path, boolean isSequential) throws IllegalArgumentException {
		validatePath(isSequential ? path + "1" : path);
	}

	/**
	 * Validate the provided znode path string
	 * @param path znode path string
	 * @throws IllegalArgumentException if the path is invalid
	 */
	public static void validatePath(String path) throws IllegalArgumentException {
		if (path == null) {
			throw new IllegalArgumentException("Path cannot be null");
		}
		if (path.length() == 0) {
			throw new IllegalArgumentException("Path length must be > 0");
		}
		if (path.charAt(0) != '/') {
			throw new IllegalArgumentException("Path must start with / character");
		}
		if (path.length() == 1) { // done checking - it's the root
			return;
		}
		if (path.charAt(path.length() - 1) == '/') {
			throw new IllegalArgumentException("Path must not end with / character");
		}

		String reason = null;
		char lastc = '/';
		char chars[] = path.toCharArray();
		char c;
		for (int i = 1; i < chars.length; lastc = chars[i], i++) {
			c = chars[i];

			if (c == 0) {
				reason = "null character not allowed @" + i;
				break;
			} else if (c == '/' && lastc == '/') {
				reason = "empty node name specified @" + i;
				break;
			} else if (c == '.' && lastc == '.') {
				if (chars[i - 2] == '/' && ((i + 1 == chars.length) || chars[i + 1] == '/')) {
					reason = "relative paths not allowed @" + i;
					break;
				}
			} else if (c == '.') {
				if (chars[i - 1] == '/' && ((i + 1 == chars.length) || chars[i + 1] == '/')) {
					reason = "relative paths not allowed @" + i;
					break;
				}
			} else if (c > '\u0000' && c < '\u001f' || c > '\u007f' && c < '\u009F' || c > '\ud800' && c < '\uf8ff'
					|| c > '\ufff0' && c < '\uffff') {
				reason = "invalid charater @" + i;
				break;
			}
		}

		if (reason != null) {
			throw new IllegalArgumentException("Invalid path string \"" + path + "\" caused by " + reason);
		}
	}
}
